1. Field of the Invention
The present invention relates to a swivel chassis for varying the mounting angle of devices such as motion picture cameras.
2. Related Art
One prior art swivel chassis for varying the mounting angle of motion picture cameras and the like comprises a stand provided with two inverted triangular legs and a base provided with two triangular legs, arranged one on top of the other so that the tips of the legs overlap. The legs connect with each other where they overlap with grooved connecting disks which engage each other to form a pivot point. Then, with support provided by the mounting bolt, the stand is made rotatable (refer to Japanese Unexamined Patent Publication 3-56261).
Another prior art arrangement has holes provided in a bottom panel of a motion picture camera on the lens side, wherein leg sections are provided so that they can emerge through these holes. By adjusting the length of the leg sections extending out of the holes, it is possible to vary the mounting angle of the motion picture camera (refer to Japanese Unexamined Patent Publication 3-20331).
However, of the two examples, quoted above, in the structure of the first swivel chassis, because the stand turns around the mounting bolt as the center of rotation, the mounting angle of the device can be varied vertically but it is not possible to change the angle horizontally. Also, with the support being provided by the mounting bolt, contact is achieved only on the bolt. Therefore, the contact area is small, resulting in limited contact resistance. This means that the holding strength of the mounting angle is limited and the angle can easily change due to vibration or the weight of the mounted device. In order to prevent this, the mounting bolt has to be tightened with considerable force, making it very inconvenient to change the mounting angle.
In the second example above, the structure of the swivel chassis makes it possible to change mounting angles only above the horizon. Also, there is the inconvenience that in order to change the photographing direction of the motion picture camera, it is necessary to change the position of the motion picture camera itself. Furthermore, if a standard motion picture camera is used, it is necessary to modify the camera at extra expense.